Switching the neutral

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askDano

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I have an equipment specification with the following sentence in it and I want to verify that this is covered in the NEC.

The sentence is: "With repect to AC control wiring, no neutral wire shall pass through the contacts of a control relay or contractor i.e. a device shall not be shut off or disengaged by breaking the device's neutral conductor."


The sentence talks about control wiring I think control or power is not to be switched.


I don't want to be repeating myself so if it is in the NEC it doesn't need to be in my spec.
 
Just remember not to gig your contractor for factory wired overloads.

I don't know of any manufacturer that doesn't break the neutral through the OL's in their motor starters.
 
This section sort of answers your question. I will look for a better reference since a relay or contactor is not a switch or breaker.

404.2(B) Grounded Conductors. Switches or circuit breakers
shall not disconnect the grounded conductor of a circuit.

Exception: A switch or circuit breaker shall be permitted
to disconnect a grounded circuit conductor where all circuit
conductors are disconnected simultaneously, or where
the device is arranged so that the grounded conductor cannot
be disconnected until all the ungrounded conductors of
the circuit have been disconnected.
 
masterinbama said:
Just remember not to gig your contractor for factory wired overloads.

I don't know of any manufacturer that doesn't break the neutral through the OL's in their motor starters.
Click to expand...

Yeah, but that is a special condition that is allowed.

430.36 Fuses ? In Which Conductor. Where fuses are
used for motor overload protection, a fuse shall be inserted
in each ungrounded conductor and also in the grounded
conductor if the supply system is 3-wire, 3-phase ac with
one conductor grounded.
 
jumper said:
Yeah, but that is a special condition that is allowed.

430.36 Fuses ? In Which Conductor. Where fuses are
used for motor overload protection, a fuse shall be inserted
in each ungrounded conductor and also in the grounded
conductor if the supply system is 3-wire, 3-phase ac with
one conductor grounded.
Click to expand...



I was referring to the overload blocks or relays built into the starter.
 
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